Extruded aluminum ceilings are widely used in cleanrooms that perform semiconductor manufacturing processes. In such a ceiling, extruded aluminum members, shaped as inverted “tee”s, are hung from the building structure above, thus forming an interstitial space in between the ceiling and the building structure.
Main tees and cross tees are usually configured in a 2′×4′ or 4′×4′ layout. Fan Filter Units (FFUs), blank pans, and lighting units then rest on the flanges of the tees. In addition, current cleanroom ceilings are generally required to carry the additional burden of Automated Material Handling Systems (AMHS) hung from below the ceiling grid.
Unlike conventional ceilings, which are quite static, cleanroom ceilings are in a constant state of change. Thus, the ceilings in cleanrooms must be easily configurable in order to adapt to changing needs.
One particular problem in current ceilings is that equipment, due to its size and weight, must sometimes be installed from below. This often forces installers to work at awkward angles to enable the equipment to pass through the grid before being leveled and lowered onto the grid. If the interstitial space is limited due to ductwork or the structure above, it may be impossible to install the equipment from below in the manner described.
Another requirement is that the ceiling be sufficiently strong to support the necessary equipment and allow maintenance personnel to move within the interstitial space to install and maintain equipment such as FFUs. A ceiling must also be strong enough to support AMHS hangers from below.
Most existing extruded aluminum ceilings are suspended on a 4′×4′ hanger layout in order to provide this type of strength. This, however, is expensive because of the number of hanger rods or anchoring rods required. It is also restrictive of the interstitial space and may present problems when installing mechanical ductwork and piping.
The speed and consequent expense of the installation and reconfiguration of extruded aluminum ceilings are overriding considerations in the cleanroom context. It is advantageous to supply a ceiling at an affordable price. It is equally important that the maintenance or installation not unnecessarily delay the operation of a cleanroom. Semiconductor prices are volatile and time sensitive. As such, interruptions or delays in the manufacturing process can be devastating. Thus, the speed of installation and reconfiguration is directly linked with the expense of the ceiling.
Another important aspect of ceilings is the number of parts involved in installation. Parts inventory can be very costly. If pieces are late or missing the entire installation process can come to a standstill. This is amplified in a cleanroom where every part must be wiped down (cleaned) prior to entering the cleanroom.
Accordingly, a need exists for an extruded aluminum ceiling that is easily configurable, sufficiently strong, and affordable and easy to install.